diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/TrafficSelector.java b/core/api/src/main/java/org/onlab/onos/net/flow/TrafficSelector.java
index ab9b4a1..bcaf70c 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/TrafficSelector.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/TrafficSelector.java
@@ -39,6 +39,15 @@
     Set<Criterion> criteria();
 
     /**
+     * Returns the selection criterion for a particular type, if it exists in
+     * this traffic selector.
+     *
+     * @param type criterion type to look up
+     * @return the criterion of the specified type if one exists, otherwise null
+     */
+    Criterion getCriterion(Criterion.Type type);
+
+    /**
      * Builder of traffic selector entities.
      */
     public interface Builder {